Add unit tests.

.travis.yml

@@ -1,6 +1,11 @@
 language: minimal
 dist: focal
 
+branches:
+  only:
+    - master
+    - /^v\d+\.\d+(\.\d+)?$/
+
 services:
   - docker
 

build.sbt

@@ -8,14 +8,16 @@ val catsEffectVersion = "2.5.1"
 val graalvmVersion = "21.1.0"
 val http4sVersion = "0.21.22"
 val jsoupVersion = "1.3.1"
+val specs2Version = "4.12.0"
 
 libraryDependencies ++= Seq(
   "org.http4s" %% "http4s-blaze-client" % http4sVersion,
   "org.http4s" %% "http4s-circe" % http4sVersion,
   "org.http4s" %% "http4s-dsl" % http4sVersion,
   "org.jsoup" % "jsoup" % jsoupVersion,
   "org.typelevel" %% "cats-effect" % catsEffectVersion,
-  "org.graalvm.nativeimage" % "svm" % graalvmVersion % Provided
+  "org.graalvm.nativeimage" % "svm" % graalvmVersion % Provided,
+  "org.specs2" %% "specs2-core" % specs2Version % Test
 )
 
 scalacOptions ++= Seq(
@@ -89,7 +91,7 @@ graalVMNativeImageOptions ++= Seq(
   "-J-Xms3072m", // Pass `-Xms3072m` directly to the JVM running the image generator
   "-J-Xmx6144m",
   "-H:+AddAllCharsets", // Make all hosted charsets available at run time.
-  "-H:+ReportExceptionStackTraces", // Show exception stack traces for exceptions during image building.).
+  "-H:+ReportExceptionStackTraces" // Show exception stack traces for exceptions during image building.).
   // Find out all options at https://chriswhocodes.com/graalvm_native_image_ce_jdk11_options.html
 )
 

src/main/scala/info/genghis/notifier/Main.scala

@@ -1,8 +1,11 @@
 package info.genghis.notifier
 
 import cats.effect._
+import cats.implicits._
 import info.genghis.notifier.config.AppConfig
 import info.genghis.notifier.error.AppError
+import info.genghis.notifier.monitor.GiftMonitor
+import info.genghis.notifier.notifier.PagerDutyNotifier
 import org.http4s.client.Client
 import org.http4s.client.blaze.BlazeClientBuilder
 
@@ -23,7 +26,7 @@ object Main extends IOApp {
   } yield ExitCode.Success
 
   def handleError(x: IO[ExitCode]): IO[ExitCode] = x.handleErrorWith {
-    case err: AppError => IO(println(err.getMessage)).map(_ => ExitCode.Error)
+    case err: AppError => IO(println(err.show)).map(_ => ExitCode.Error)
     case other         => IO(other.printStackTrace()).map(_ => ExitCode.Error)
   }
 

src/main/scala/info/genghis/notifier/error/AppError.scala

@@ -1,19 +1,17 @@
 package info.genghis.notifier.error
 
+import cats.Show
 import io.circe.Json
 import org.http4s.Status
 
 sealed trait AppError extends Throwable
 
 object AppError {
-  implicit class AppErrorOps(appError: AppError) {
-    def getMessage(): String = appError.toString
-    override def toString: String = appError match {
-      case PagerDutyTriggerError(request, body)       => s"Cannot trigger PagerDuty $request with body: $body"
-      case WatchingError(errStatus, errPayload) => s"Cannot watch destination web page, got $errStatus, $errPayload"
-      case MissingApplicationConfigError        => "Missing required environment variables"
-      case NoDestinationGoodFoundError          => "Cannot find the destination good"
-    }
+  implicit val showAppError: Show[AppError] = Show.show {
+    case PagerDutyTriggerError(request, body) => s"Cannot trigger PagerDuty $request with body: $body"
+    case WatchingError(errStatus, errPayload) => s"Cannot watch destination web page, got $errStatus, $errPayload"
+    case MissingApplicationConfigError        => "Missing required environment variables"
+    case NoDestinationGoodFoundError          => "Cannot find the destination good"
   }
 }
 

src/main/scala/info/genghis/notifier/GiftMonitor.scala → src/main/scala/info/genghis/notifier/monitor/GiftMonitor.scala

@@ -1,4 +1,4 @@
-package info.genghis.notifier
+package info.genghis.notifier.monitor
 
 import cats.effect.Sync
 import cats.implicits._

src/main/scala/info/genghis/notifier/PagerDutyEvent.scala → src/main/scala/info/genghis/notifier/notifier/PagerDutyEvent.scala

@@ -1,4 +1,4 @@
-package info.genghis.notifier
+package info.genghis.notifier.notifier
 
 import io.circe.syntax._
 import io.circe.{Encoder, Json}

src/main/scala/info/genghis/notifier/PagerDutyNotifier.scala → src/main/scala/info/genghis/notifier/notifier/PagerDutyNotifier.scala

@@ -1,4 +1,4 @@
-package info.genghis.notifier
+package info.genghis.notifier.notifier
 
 import cats.effect.Sync
 import cats.implicits._

src/test/scala/info/genghis/notifier/config/AppConfigSpec.scala

@@ -0,0 +1,32 @@
+package info.genghis.notifier.config
+
+import cats.effect.IO
+import info.genghis.notifier.error.MissingApplicationConfigError
+import org.specs2.mutable.Specification
+
+class AppConfigSpec extends Specification {
+
+  "AppConfigSpec" >> {
+    "loadConfigFrom" should {
+      "generate AppConfig if all environment variables are valid" in {
+        val env = Map(
+          "WATCH_URL" -> "http://watch.url",
+          "PAGER_DUTY_URL" -> "https://pagerduty.utl",
+          "PAGER_DUTY_API_KEY" -> "PAGERDUTY_API_KEY"
+        )
+        AppConfig.loadConfigFrom[IO](env).unsafeRunSync() must_== AppConfig(
+          "http://watch.url",
+          "https://pagerduty.utl",
+          "PAGERDUTY_API_KEY"
+        )
+      }
+
+      "raise error if some environment variables are missing" in {
+        val env = Map(
+          "WATCH_URL" -> "http://watch.url"
+        )
+        AppConfig.loadConfigFrom[IO](env).unsafeRunSync() must throwA(MissingApplicationConfigError)
+      }
+    }
+  }
+}

src/test/scala/info/genghis/notifier/error/AppErrorSpec.scala

@@ -0,0 +1,26 @@
+package info.genghis.notifier.error
+
+import cats.implicits._
+import io.circe.Json
+import org.http4s.Status
+import org.specs2.mutable.Specification
+
+class AppErrorSpec extends Specification {
+  "AppErrorSpec" >> {
+    "AppError" should {
+      "show error message" in {
+        val pagerDutyTriggerError: AppError = PagerDutyTriggerError("Test", Json.obj())
+        pagerDutyTriggerError.show must_== "Cannot trigger PagerDuty Test with body: {\n  \n}"
+
+        val watchingError: AppError = WatchingError(Status.NotFound, "")
+        watchingError.show must_== "Cannot watch destination web page, got 404 Not Found, "
+
+        val missingApplicationConfigError: AppError = MissingApplicationConfigError
+        missingApplicationConfigError.show must_== "Missing required environment variables"
+
+        val noDestinationGoodFoundError: AppError = NoDestinationGoodFoundError
+        noDestinationGoodFoundError.show must_== "Cannot find the destination good"
+      }
+    }
+  }
+}